Nitroethylenes



NITRQETHYLENES Dale N. Robertson, Midland, :-Mich., assignor to The DowChemical .Company, Midland, Micln, a corporation of Delaware No Drawing.Application October 18, 1956 Serial No. 616,653

6 Claims. (Cl. 260645) This invention relates .to nitroethylenes :havingthe structure N R-'oH o-R' oxy-1-naphthyl-, 2-ethoxy-1-naphthyl-, and2,4-dinitro-1*-- naphthyl-. The expression aryl radical of the benzeneseries refers to phenyl and substituted phenyl radicals such as3-nitrophenyl-, 2-chlorophenyl-, 4-bromophenyl-, 2,4-dimethylphenyl-,4-ethoxyphenyl-, 2-bromophenyl-, 4- phenylphenyl-, 2-fluorophenyl-,4-methoxyphenyland 3- chlorophenyl-.

The products of this invention are yellow or orangecolored crystallinesolids soluble in organicsolvents such as ethanol, acetone, xylene andkeroseneand substantially insolublein water and IOpercent aqueous sodiumhydroxide solution. 'The products are useful .as toxic ingredients incompositions adapted to be employed for the control of bacteria andfungi such as in germicidalsoap compositions and in the preservation ofcellulos'ic textiles. They are'also useful as agricultural chemicals andas insecticides. In addition, these compounds are useful as chemicalintermediates.

The products of this invention may be prepared by.the reaction of (l) aSchiff base having the structure wherein R" is a lower. alkyl radicalcontaining from-3 to 6 carbon atoms, inclusive, with (2) a nitromethanecompound having the structure CHPR The Schiif base reactant may beprepared by condensing an appropriate aldehyde having the formula RCHOwith'a primary amine having the formula R"NH I wherein R and R" are asabove defined. It is convenient to prepare the Schiff baseas a firststep in the synthesis of the nitroethylene.

In the preferred method for carrying out this reaction, the aldehyde anda primary alkyl amine, such asnormalbutylamine, are mixed in awater-immiscible organic solvent such as benzene or cyclohexane. Goodresults are obtained when substantially equimolar quantities of thereactants or a slight excess of the amine are employed. The resultingmixture is heated to distill out the Water of reaction substantiallyastormed as an azeotropic mixture. After completion-of the reaction, theremaining solvent and excess amine, if employed, are'removecl bydistillation and the Schitl base recovered as residue. The latter may bepurified by conventional means, if desired.

in the second step of the reaction, the Schitt base and the nitromethanecompound are mixed together in fllSl-lbstantiallyanhydrous loweralkanoicacid such as acetic, vpropionic or butyric acid. Substantially equimolarproportions of the Schifi base-and nitromethane'compound and a molarexcessof thealkanoicacid are employed. The preferredexcessof the acid isfrom "2'to3"molar"excess. The resulting mixture is.allowed to stand atroom temperature, i. e., from about'20'-40 C. to allowthe reactiontoproceed. The reaction is usually substantially Example 1.-1-.(B-nitr0styryl) naphthalene IN05: V OH=( J 15 .grams .(.0.1 mole)of l-naphthaldehyde, 1O milliliters (0.1 mole) of normalabutylamin'e-and50'milli1iters of benzene are mixed together and the resultingmixtureheated to distill off the water of reaction .asa benzenewater azeotrope.Theremainingbenzene is distilled out under reduced pressure to obtainanN-( l-naphthylidene)- normal-.butylamine product as residue.

13.7 grams (0.1 mole) of .phenylnitromethane and-20 milliliters ofglacial acetic acid are-addedto theiabove residue and the resultingmixture stirred. An exothermic reaction takes place. The mixture isplaced in-the dark and allowed to stand overnight to obtainayellow-crystalline solid l-(,8-nitrostyryl)naphthalene product. Thelatter is filtered from the mixture and recrystallizedfrom ethanol toobtain a purified product melting at 122"- 122.5 C. The yield of thefirst crop of the recrystallized product is 18.9 grams or 68.7 percentof theoretical.

Example 2.-2- (p-nitrostyryl) naphthalene 15 grams (0.1 mole) ofZ-naphthaldehyde, 10 milliliters (0.1 mole) of.normal-butylamine.andmilliliters of benzeneare mixed together and theresulting mixture heatedto distill off the water of reaction as a benzenewater azeotrope. Theremaining benzene is distilled out under reducedpressure to obtain anN-(2-naph thylidene)- normal-butylamine product as residue.

13.7 grams (0.1 mole) of phenylnitromethane'and '20 milliliters ofglacial acetic acid are added tothe'above residue and the resultingmixture "is stirred. An-exothermic reaction takes place. The mixture isplaced in the dark and'allowed to stand overnight'to obtain a yellowcrystalline solid. The latter is filtered from the mixture and purifiedto obtain a 2-(}8-nitrostyryl)naphthalene product having a molecularweight of 275.

Example 3.--5-br0m0-1- (B-nitrostyryl) naphthalene who 23.5 grams (0.1mole) of S-bromo-l-naphthaldehyde, milliliters (0.1 mole) ofnormal-butylamine and 75 milliliters of benzene are mixed together andthe resulting mixture heated to distill off the water of reaction as abenzene-water azeotrope. The remaining benzene is distilled out underreduced pressure to obtain an N-(S-bromo-l-naphthylidene)-norma1-butylamine product as residue.

13.7 grams (0.1 mole) of phenylnitromethane and milliliters of glacialacetic acid are added to the above residue and the resulting mixturestirred and allowed to stand overnight in the dark to precipitate ayellow solid product. The latter is filtered from the mixture to obtaina 5-bromo-1-( e-nitrostyryhnaphthalene product hav ing a molecularweight of 354.2.

28.0 grams (0.1 mole) of 5-brorno-8-nitro-1-naphthaldehyde, 1Omilliliters (0.1 mole) of normal-butylamine and 75 milliliters ofbenzene are mixed together and the resulting mixture heated to distilloff the water of reaction as a benzene-water azeotrope. The remainingbenzene is distilled out under reduced pressure to obtain anN-(5-bromo-8-nitro-l-naphthylidene)-norma1- butylamine product asresidue.

13.7 grams (0.1 mole) of phenylnitromethane and 20 milliliters ofglacial acetic acid are added to the above residue and the resultingmixture stirred and allowed to stand overnight in the dark toprecipitate a yellow solid product. The latter is filtered from themixture to obtain a 5-bromo-8-nitro-1-( fi-nitrostyrybnaphthaleneproduct having a molecular weight of 399.2.

Example 5 -1 -(2-ch lora-fl-nitrastyryl -2,7 -dimeth0xynaphthalene CH= BCHaO O CH: C]

21.6 grams (0.1 mole) of 2,7-dimethoxy-1-naphthaldehyde, 10 milliliters(0.1. mole) of normal-butylamine and 75 milliliters of benzene are mixedtogether and the resulting mixture heated to distill off the Water ofreaction as a benzene-water azeotrope. The remaining benzene isdistilled out under reduced pressure to obtain anN-(2,7-dimethoxy-l-naphthylidene) normal butylamine product as residue.

17.2 grams (0.1 mole) of 2-chlorophenylnitromethane and milliliters ofglacial acetic acid are added to the above residue and the resultingmixture stirred and allowed to stand overnight in the dark toprecipitate a solid product. The latter is filtered from the mixture toobtain a 1-(2-chloro-fi-nitrostyryl)-2,7-dimethoxynaphthalene producthaving a molecular Weight of 369.8.

Example 6.--1-(Z-fluoro-fimitrostyryl) -8-nitr0- naphthalene 20.1 grams(0.1 mole) of 8-nitro-1-naphthaldehyde and 10 milliliters (0.1 mole) ofnormal-butylamine and 75 milliliters of benzene are mixed together andthe resultingmixture heated to distill off the water of reaction as abenzene-water azeotrope. The remaining benzene is distilled out underreduced pressure to obtain an N-(S-nitro-l-naphthylidene)-normal-butylamine product as residue.

15.5 grams (0.1 mole) of 2-fluorophenylnitrornethane and 25 millilitersof glacial acetic acid are added to the above residue and the resultingmixture stirred and allowed to stand overnight in the dark toprecipitate a solid product. The latter is filtered from the mixture toobtain a I-(Z-fluoro-fi-nitrostyryl)-8-nitronaphthalene product having amolecular weight of 338.3.

Example 7.-4-chlar0-1-(4-nitro-fl-nitr0styryl) naph thalene 19.1 grams(0.1 mole) of 4-chloro-l-naphthaldehyde, 10 milliliters (0.1 mole) ofnormal-butylamine and 75 milliliters of benzene are mixed together andthe resulting mixture heated to distill oil the water of reaction as abenzene-water azeotrope. The remaining benzene is distilled out underreduced pressure to obtain an N- (4-chloro-l-naphthylidene)-norrnal-butylamine product as residue.

18.2 grams (0.1 mole) of 4-nitrophenylnitromethane and 25 milliliters ofglacial acetic acid are added to the above residue and the resultingmixture stirred and allowed to stand overnight in the dark toprecipitate a solid product. The latter is filtered from the mixture toobtain a 4-chloro-1-(4-nitro-B-nitrostyryl)naphthalene having amolecular weight of 354.8.

In similar preparations the following nitroethylenes are prepared:

2-(4 chloro-fi nitrostyryl) 6 methoxynaphthalene having a molecularweight of 339.8 by the reaction of 6-methoxy-2-naphthaldehyde withnormal-propylamine to obtain N-(6 methoxy-2-naphthylidene)normal-propylamine followed by the reaction of the latter with 4-chlorophenylnitromethane.

2 (4 hromo-;3-nitrostyryl) 5 chloro 6 methoxynaphthalene having amolecular Weight of 418.7 by the reaction of5-chloro-6-methoxy-2-naphthaldehyde with normal-butylarnine to obtain anintermediate N-(S- chloro-6-methoxy 2 naphthylidene) normal butyl' aminefollowed by the reaction of the latter with 4- brom-ophenylnitromethane.

4-methyl-l-(3-nitro-p nitrostyryl)naphthalene having a molecular weightof 334.3 by the reaction of 4-methyll-naphthaldehyde withnormal-amylamine to obtain an N(4-methyl-l-naphthylidene)normal-amylamine intermediate followed by thereaction of the latter with 3- nitrophenylnitromethane.

1-(3-bromo-B-nitrostyryl)-2 methoxy 6 nitronaphthalene having amolecular weight of 413.2 by the reaction of2-methoxy-6nitro-l-naphthaldehyde with normal-butylamine to obtain anN-(2-methoxy-6-nitro-1- naphthylidene)-normal-butylarnine intermediatefollowed by the reaction of the latter with 3-bromophenylnitromethane.

The products of this invention are useful for the control of bacterialand fungal organisms. In a representative operation,l-(fi-nitrostyryl)naphthalene was added to nutrient agar media to give asaturated solution and the media streaked with Penicillium digitatum andincubated at 30 C. for three days. At the end of this period, completeinhibition of growth of the organism was observed.

The products are also useful as toxicants in germicidal preparations. Ina representative operation, a germicidal soap preparation was made byadding l-(B-nitrostyryl)naphthalene to a 5 percent soap solution to givea concentration of 0.025 percent. The resulting solution was inoculatedwith Staphylococcus aureus and incubated for 4 hours at 37 C. At the endof this period, nutrient agar slants were swabbed with the inoculatedsoap solution and incubated for 24 hours at 37 C. On examination of theslants at the end of this period, no bacterial growth was observed.

A preferred method for the preparation of these compounds is disclosedand claimed in a copending application Serial No. 616,652, filedconcurrently herewith, in the name of Dale N. Robertson.

Certain of the Schiff bases employed in the synthesis of thenitroethylenes of the present invention are described and claimed in acopending application of Dale N. Robertson, filed concurrently herewithas Serial No. 616,659.

The nitromethane compounds employed as starting materials in thepreparation of the nitroethylenes of this invention may be prepared byreacting an appropriate benzyl bromide having the structure with sodiumnitrite in a solvent such as dimethylforrnamide at a temperature of from-20 to 15 C. for several hours. The fluorophenylnitromethanes employedin the preparation of certain of the nitroethylene of the presentinvention are described and claimed in a copending application by DaleN. Robertson, filed concurrently herewith as Serial No. 616,655.

I claim: 1. A nitroethylene having the structure R-0H=0R' wherein Rrepresents an aryl radical of the naphthalene series consisting ofnaphthyl and substitued naphthyl radicals wherein the substituent is atleast one of a group consisting of lower alkoxy, lower alkyl, nitro andhalo; and R represents an aryl radical of the benzene series consistingof phenyl and substituted phenyl radicals wherein the substituent is atleast one of a group consisting of nitro, halo, phenyl, lower alkyl andlower alkoxy.

. 1- (,B-nitrostyryl) naphthalene.

. 2-(fi-nitrostyryl)naphthalene.

. S-bromo-l-(fi-nitrostyryl)naphthalene.

1- (Z-fluoro-[S-nitros tyryl -8-nitronaphthalene.4-chloro-1-(4-nitro-B-nitrostyryl)naphthalene.

No references cited.

1. A NITROETHYLENE HAVING THE STRUCTURE